The poll conducted for The Des Moines Register shows Romney, the former Massachusetts governor, with support from 23 percent in Iowa. Bachmann is right on his heels. The Minnesota representative who plans to launch her campaign in Iowa Monday has support from 22 percent.

Romney was the No. 2 finisher in the caucuses in his bid for the 2008 GOP nomination. Bachmann is a three-term congresswoman and newer face in the 2012 White House mix.

The results are based on telephone interviews with 400 likely Republican Iowa caucus-goers from June 19 to 22. It has a margin of error of plus or minus 4.9 percentage points.